Optical Emission Spectroscopy of Plasma of Electric Spark Discharge between Metal Granules in Liquid
Murmantsev O.O.1, Veklich A.M.1, Boretskij V.F.1
1 Faculty of Radio Physics, Electronics and Computer Systems, Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., Kyiv, 01601, Ukraine
E-mail: murmantsev.aleksandr@gmail.com

Currently, the electric discharges burning in the liquid are of great interest. Among the numerous applications of such discharges, the synthesis of nanoparticles is most relevant and demanded issue among scientists. This is caused by widespread use of nanoparticles in various branches. In particular, the colloidal solutions with nanoparticles of different metal (in particular, copper, silver, molybdenum, etc.) have excellent bactericidal, antiviral, antifungal and antiseptic effects, what makes them essential biocide products.
The investigation of plasma of discharge in liquid between metal granules is carried out directly in the discharge chamber of the installation, specially developed for the synthesis of colloidal substance with metal nanoparticles. The influence of different energy input on the main plasma parameters was understudy.
It is nature that to improve the characteristics and properties of solutions with nanoparticle it is necessary to investigate directly the process, which occurs during nanoparticles formation. Namely, the plasma of discharges, which burns between granules used as a source of metal particles in the obtained solutions, should be understudy. The most suitable approach to such investigation is optical emission spectroscopy. On the one hand, this method enables to obtain with sufficient accuracy the main plasma parameters, such as temperature and electron density, which characterise the processes of nanoparticles formation. On the other hand, such technique does not perturb the plasma and cannot affect the properties of the resulting product.
Therefore, optical emission spectroscopy methods are used to determine main plasma parameters. Namely, the excitation temperature is determined by the Boltzmann plots technique. The electron density is obtained from width of certain spectral lines, the dominant broadening mechanism of which is Stark effect.